The present disclosure relates to an image display apparatus such as a projector, and a method of controlling the image display apparatus.
In the past, an image display apparatus such as a projector is widely used. For example, according to Japanese Patent Application Laid-open No. H06-317777, a projector divides light from a light source into three primary colors i.e., RGB (red, green, and blue), projects the divided light onto a liquid crystal via filters, and displays the light on a screen.
As shown in FIG. 1 of Japanese Patent Application Laid-open No. H06-317777, in a projector 1, three primary colors reach a liquid crystal 8. A three-primary-color intensity detector 20 is a silicon photo diode and includes three-color color filters. The three-primary-color intensity detector 20 detects scattered light of the three primary colors. Then the three-primary-color intensity detector 20 outputs intensity of the three primary colors, i.e., a signal Z corresponding to red (R), a signal Y corresponding to green (G), and a signal X corresponding to blue (B), to a controller 30. The controller 30 calculates a correction value for correcting color shift based on the intensity of the three primary colors detected by the three-primary-color intensity detector 20 such that light projected onto the liquid crystal 8 may have a predetermined white color. The controller 30 outputs the correction value to a driving voltage generator 31. According to Japanese Patent Application Laid-open No. H06-317777, the correction value is calculated as described above, whereby it is possible to correct color shift easily and to reproduce a predetermined white color constantly (Japanese Patent Application Laid-open No. H06-317777, paragraphs [0021], [0022], [0027], etc.).